I read in one of my many books that i should leave the piglets in their enclosure and move the mother so that they are used to their own area whilst mum is gone, is this right?
We generally move mum back to the boar (if she is mating immediately) or to the field (if she is having a month off) and at the same time move the weaners to one of our weaner pens, freeing the farrowing shed space for the next incumbant. We have seen no problems in moving 8 week old piglets to a "new" area - they seem to settle in very quickly, make themselves a new bed, find feed and water and enjoy exploring new environment.
also how far away should i put Manda is out of sight far enough
Some sows are more motherly than others, and frankly some you could put two feet away and they'd be fine, others will call for their young for ages. Out of sight is the gerneral minimum requirement, if you can get them out of hearing (50 yards!) so much the better, but usually that is not possible. As long as mum is secure so she cannot get out, you should be ok.
I was also thinking should i put her in with a couple of other sows or would she be agitated and aggressive with the separation and better on her own?
Re-introducing sows back to a group will force the group to re-establish their order of seniority. If the sow going back is top pig, she will quickly regain her leadership. If she is bottom pig, she will again get quickly back into place. However a middle ranking pig will have to confront all the others to work out who is who, so can get quite scratched as their work themselves out. If she is in poor condition, consider a few days alone to build some strength back up before putting her back. Key rule to re-introducing adult pigs is to do it in a large pen, where there is “flight” space – a losing pig needs to be able to run about 20 yards away from her aggressor. If she can do this she will, but if she can’t she’ll will carry on fighting in vain, and can get badly injured. With space to flight it is rare that injuries occur.